I have a similar problem but for a different reason perhaps. I have a simple, single LPT set up with a home made breakout board and a single index pulse. With Mach3 R3.042.020 Turn, this works fine and I see a stable and accurate spindle speed from 50 to 2000rpm and I can thread well (given the known limitations of this version).
However, I updated to Mach3 R3.042.040 for the threading corrections and now I have no spindle speed in the DRO or in the Turn Diagnostics. Back to version 020 and its fine. I've tried to read up on this and read Rich's pdf but can't see where I've got it wrong.
I know there have been quite a few changes between vn 020 and vn 040, can anyone help me with why I would loose spindle speed? Is there a setting or approach I need to change to get this working? I can see the index pulse in diagnostics when I turn the spindle by hand but over 50rpm its gone. I've tried with turn diags enabled and without, which made no difference.
Is the new driver approach compatible with Win2000 and 1GHz P4 machine? Everything else seems fine and Mill works great as does my MPG with Turn and Mill at vn 040, just no Speed reading and presumably, no threading!
Thanks,
Woody.